Method of threading a blank



April'28, 1925. 1,535,553

5 A. STAMBACH METHOD OF THREADING A BLANK Filed June 5, 1921 ply .1

; A.TTORNEY vide a blade of such form that the handle Fatented Apr. 28, 1925.

UNITED STATES PATENT OFFICE.

ARTHUR STAMBACH, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC 66 MANUFACTURING QOMI'ANY, A CQRIPOR-ATION OF PENNSYL- VANIA.

METHOD 1 or rnanamne A BLANK.

Application filed June 3, 1921. Serial No. 474,720.

To all whom it may concern:

Be it known that I, ARTHUR STAMBAOH, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods o1 Threading a Blank, of which the following is a specification.

My invention relates to knife-blade switches and particularly to theblades there of and the method of making of the same.

, My invention has for its object the provision of a knife-blade switch, that may be manufactured at a low. cost and which is oi substantial construction, and also to promay be readily attached thereto.

Another object of my invention is to provide an improved method of making switch blades and similar devices.

A further object of my invention is to provide an improved method of making switch blades and similar devices from standard rodmaterial.

I accomplish the foregoing objects by the employment of a bar of copper or similar material which has one portion thereof stamped or otherwise formed to the proper contour and which is so upset or thickened at one of its ends that sufficient material will be provided for the attachmentiof a handle, thus avoiding the necessity of applying a special fastening device thereto to which a handle may be secured.

As illustrated in the accompanying draws,

Figure 1 is a top plan view of a. switch that embodies my invention.

Fig. 2 is a side elevational view of the switch shown in Fig. 1.

Fig. 3 is a detail view of: one of the blade members employed in the device of F 1 and 2, and

Figs. 1, 5 and 6 are detail views of modified terms of bladeconstruction.

The switch comprises hinge-jaw members '2', upon which the blades 8 are pivoted, jaw members 9, a cross bar 10 attached to the blade members 8, and a handle 11 that is secured to the cross bar 10.

The blade members 8 are formed preferably ot material such as copper rods and for a portion of their length are stamped or rolled into a kniteblade form. At one end, a hole 12 is provided for the reception of a pivot pin. The bar or red is sw'aged or upset at the other end by means of dies, making a thickened portion 13. This thickened portion may be tapped forthe reception of a screw 14 that is employed for attaching the cross bar 10 to the blade member.

In Fig. 4;, I have shown a blade formed by flattening a rod 16 for a portion of its length, leaving the other portion, 17 thereof in its original form, in order to employ it as a securing bolt. In this form, the cross bar would be provided with suliiciently large holes for the reception of the end 17, which may be threaded. place on top of the bar to hold it in position. Instead of threading the portion 17, the end thereoi may be upset after the cross A nut is screwed into bar has been placed thereon, to retain the 1 cross bar in position.

In Fig. 5, a blademember 18 is formed with an extended portion 19, by means of dies. The extension 19 has curved sides and is slightly flattened at its top and bottom portions. It will be seen that the enlarged portion .19 overlaps the end of the body of the blade. This construction provides the necessary strength at the juncture of the enlarged portion with the blade member.

By upsetting the end portion 19 of: the blade member 18 in the manner shown, it is possible to press threads into the extended portion by means of dies, without seams or fins appearing on the extension at the point opposite thefaces of the-dies.

The preferred sequence of stamping operations consists in first upsetting a portion of the metal] stock, next stamping another portion of the stockinto the shape of the finished blade portion and, during the same operation, shaping a tang for the handle from the upset portion and adjacent stock,

then pressing threads on the tang by means in the accompanying claims.

that the metal in the flat surfaces will not flow towards the abutting surfaces of the dies sufliciently far to creep into the crevices therebetween. The amount of flattening necessary to secure. an uninterrupted thread may be calculated closely enough that metal will not be forced into the spaces between the dies. In those cases wherein the flattened portions are not fully rounded out by the threading dies, the threads will, nevertheless, be of proper pitch and sufticiently accurate to be properly engaged by a clamping nut.

The completed form of the blade of Fig. 5 is shown in Fig. 6. In this case, as in the construction of Fig. 4-, the cross bar 10 may be properly perforated adjacent to its ends, the latter members inserted in the perforations and nuts then screwed into position to clamp the cross bar in place.

From the foregoing, it will be seen that I provide a blade member which has a fastening means that is unitary therewith and which, nevertheless, has the required amount of strength and is of simple form.

My device is not limited in its application to switch blades, and various modifications may be made therein without departing from the spirit of the invention as defined For instance, the blade member maybe provided with a relatively thick portion at a point intermediate its ends, and the invention is apolicable to single blade switches as well as to switches provided with two or more blades.

I claim as my invention:

1. The method of externally threading a blank which consists in impressing a threaded die upon a portion thereof and causing the material to flow into a portion of the die.

2. The method of threading a blank which consists in providing a flattened face on said blank, then displacing the material of the blank to substantially fill out the flattened portion and provide a thread thereon.

3. The method of threading a blank which consists in providing flattened opposite faces on said blank, then displacing the material of the blank to substantially fill out the flattened portions and provide a thread thereon.

at. The method of threading a blank which consists in providing a flattened surface on said blank, then exerting pressure upon the material of said blank in such manner that threads are formed upon the surface of said blank and the excessmaterial fills out said flattened surface.

5. The method of threading a round blank=which consists in providing a flattened surface on said blank, then exerting pressure upon the material of said blank in such manner that threads are forn'icd upon the surface of said blank and-the excess material fills out said flattened surface.

In testimony whereof, I have hereunto subscribed my name this 23rd day of May ARTHUR 'STAMBACH. 

